Cellular onc genes: their role as progenitors of viral onc genes and their expression in human cells

Abstract

Viral transforming (v-onc) genes are derived from cellular (c-onc) genes that are highly conserved among vertebrates. Comparative studies of v-onc and c-onc genes have shed some light on the mechanism leading to formation of the transforming viruses. A specific example of the sis gene is presented here for illustration. Studies on the expression of six c-onc genes in human cells revealed at least three categories of onc genes: (a) those that are universally expressed and probably are important in basic cellular functions, (b) those that are not detectably expressed in the cells examined and may have very transient expression in development, and (c) those that are only expressed in specific cell types and may be important in tissue differentiation. Our studies do not show conclusively a role of these onc genes in human neoplasias.